Generally, top sealing covers used for such small bottles as medicine bottles are made of a thin aluminum sheet, and therefore, they can be opened readily with bare hands at any place without an opener.
However, bottle caps which are used to seal bottles with a certain level of pressure formed therein, as in beer bottles and carbonate beverage bottles, are made of a thick high strength metal in order to firmly seal off the bottles with a certain level of pressure formed therein. Therefore, unlike the thin aluminum bottle caps, the high strength metallic sealing covers cannot be opened without using a separate cap opener, when the contents of the bottles are to be drunk.
However, people have to detach bottle caps to drink beer and beverages not only indoors but also in other places such as roads and open fields. When they drink indoors, there are available bottle cap openers in most cases, and therefore, there is encountered no special inconvenience. However, when bottles are opened outdoors, people have to experience much difficulty.
Further, even in the case where a cap opener is available, if the cap opener is small, people have a hard time finding the cap openers within the rooms.
There is a prior art of the bottle cap having an integral cap opener, and this prior art is disclosed in Korean Utility Model Registration No. 58923 which is granted to the present applicant. In this prior art, an elongate opener extends downwardly from a side of the bottle cap, and a space is formed on the portion where the cap opener meets the bottle cap, while the body of the cap opener is provided with an elongate bending line so as for the strength of the opener to be reinforced.
In this prior art, if the body of the opener is lifted up and then turned in the opposite direction, then the upper portion of the body of the opener is folded around the above mentioned space, thereby opening the bottle cap in an easy manner. However, when the body of the opener is folded, the portion between the bottle cap and the upper end of the body of the opener forms a sharp projection, and therefore, the user is apt to be hurt, if special care is not exercised. Further, even with the reinforcing bending line of the body of the opener, the body can be bent during use, while the adherence of the opener to the bottle makes it difficult to lift up the opener. Further, the opener is provided with only the function of opening the cap, and therefore, there is missing the aesthetic considerations for the opener.